Describe 2 experiments that led to a major change in the model of the atom

"The Geiger–Marsden experiment (also called the Gold foil experiment or the Rutherford experiment) was an experiment to probe the structure of the atom performed by Hans Geiger and Ernest Marsden in 1909,[1] under the direction of Ernest Rutherford at the Physical Laboratories of the University of Manchester. The unexpected results of the experiment demonstrated for the first time the existence of the atomic nucleus, leading to the downfall of the plum pudding model of the atom, and the development of the Rutherford (or planetary) model." 

The plum pudding model

\Rutherfords gold foil experiment

Igonna be honest i dunno that one srry

D)can be increased in a closed system